package com.nowcoder.community.controller.advice;

import com.nowcoder.community.util.CommunityUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;


/**
 * 统一异常处理 不需要在任何一个controller上单独处理
 */
@ControllerAdvice(annotations = Controller.class) // 所有带有controller注解的bean都能被扫描到
public class ExceptionAdvice {

    private static final Logger logger = LoggerFactory.getLogger(ExceptionAdvice.class);

    @ExceptionHandler(Exception.class)
    public void handleException(Exception e, HttpServletRequest request, HttpServletResponse response) throws IOException {
        logger.error("服务器发生异常：" + e.getMessage());
        for (StackTraceElement element : e.getStackTrace())
            logger.error(element.toString());

        String xRequestedWith = request.getHeader("x-requested-with"); // 判断请求是普通的还是异步的
        if("XMLHttpRequest".equals(xRequestedWith)){ // 表示这是一个异步请求
            response.setContentType("application/plain;charset=utf-8");
            PrintWriter writer = response.getWriter();
            writer.write(CommunityUtil.getJSONString(1, "服务器异常"));
        }else
            response.sendRedirect(request.getContextPath() + "/error");
    }

}
